title: Sewage sludge bioleaching by indigenous sulfur-oxidizing bacteria: effects of ratio of substrate dosage to solid content.
abstract: The aim of this work was to study the effect of ratio of substrate dosage to solid content (Sd/SC) on sewage sludge bioleaching. The inocula--indigenous sulfur-oxidizing bacteria were enriched and cultured from the fresh activated sludge to a wastewater treatment plant. The results showed that Sd/SC significantly influenced the sludge bioleaching process. With increase in Sd/SC the sludge bioleaching was enhanced, which was represented by the acceleration of sludge acidification, oxidizing environment formation, and substrate (sulfur) utilization. Higher Sd/SC was more efficient to solubilize the heavy metals and total phosphorus (TP) than lower Sd/SC, while total nitrogen (TN) release was not influenced by Sd/SC. Zinc and copper were efficiently bioleached because of sludge acidification and sludge oxidation, but lead was bioleached with a low efficiency because of the formation of low soluble PbSO(4) precipitates. After bioleaching the biotoxicity of sewage sludge greatly reduced.
authors.affiliation: School of Environmental Science and Engineering, Beijing Forestry University, Beijing, China. panyuez@hotmail.com
authors.forename: Panyue
authors.initials: P
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhu
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhang
authors.forename: Sai
authors.initials: S
authors.lastname: Zou
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wu
mesh_terms: D001105:Archaea / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods; D019216:Metals, Heavy / Q000302:isolation & purification / Q000378:metabolism*; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology*; D013455:Sulfur / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D019216:Metals, Heavy; D012722:Sewage; D014874:Water Pollutants, Chemical; D013455:Sulfur